Bug 1526822 - Fix headless screenshot that has redirects. r=mossop
The changes in bug 1507352 caused onLocationChange events to be ignored
when there was an http redirect. This caused the screenshot command to hang
since it never attached an event listener on the page it was redirected to.
Differential Revision: https://phabricator.services.mozilla.com/D22220

bug 846581 - avoid nsIBadCertListener2 in toolkit install/update tests r=mossop
This patch changes how some toolkit mochitest-browser-chrome tests set up
certificate error overrides to avoid using nsIBadCertListener2 (basically it
follows the approach of exceptionDialog.js and uses the onerror callback of the
XHR).
Differential Revision: https://phabricator.services.mozilla.com/D21818